Perhaps you should try some spelling variations:
"dopnauschwabisches schrifttum heft 1" » "donauschwabisches schrifttum heft 1" (Expand Search), "donauschwabisches christentum heft 1" (Expand Search), "dopnauschwabisches schrifttum heft 3" (Expand Search)
"donauschwabische schrifttum heft 2" » "donauschwabisches schrifttum heft 2" (Expand Search), "donauschwabisches christentum heft 2" (Expand Search), "donauschwabische schrifttum heft 3" (Expand Search)

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"dopnauschwabisches schrifttum heft 1\") OR (\"donauschwabische schrifttum heft 2\"))~".
• Removing quotes may allow a broader search: (( dopnauschwabisches schrifttum heft 1 ) OR ( donauschwabische schrifttum heft 2 ))~.
• Adding a wildcard symbol may retrieve word variants: (("dopnauschwabisches schrifttum heft 1") OR ("donauschwabische schrifttum heft 2"))*.